Mechanical systems may be configured to provide motion according to a specified design. For example, gears may be configured to mesh such that rotation of a first gear imparts a conforming rotation of the second gear. As another example, a rack and pinion gear assembly may be configured to mesh such that rotation of the pinion gear imparts a conforming translation of the rack. Such systems may be employed in a variety of applications including robotics, transportation devices, power systems, household appliances, and the like.
An exemplary application of a mechanical system is in the deployment and actuation of a control surface system for a projectile. For a projectile having a control surface, there are at least two design issues: selective deployment and/or selective actuation of the control surface. As to deployment, in many applications it is desirable to stow the control surface at some point during the operation of the projectile. For example, a projectile may be configured to be fired from an artillery barrel. In order to maximize the kinetic energy imparted to an artillery fired projectile, the projectile may be configured with an outer diameter such that the projectile is substantially flush with the interior surface of the barrel. Because control surfaces are frequently configured to extend beyond the outer diameter of the projectile, it is may be necessary to stow the control surface and deploy it after the projectile is in flight.
As to actuation, a control surface may be configured to actuate in flight to modify the trajectory of the projectile. For example, a control surface may be configured to rotate about an axis substantially normal to the longitudinal axis of symmetry of the projectile in order to modify the surface characteristics of the projectile. Accordingly, a system may be implemented to actuate the control surface to a desired position.
Complex mechanical systems have been developed to achieve these deployment and actuation applications. For example, many control surface systems include pyrotechnic actuators configured to provide irreversible control surface implementations. As another example, many control surface systems include feedback mechanisms to selectively align a control surface. Such systems may increase the complexity of hardware and software components and may increase power consumption. Complexity may increase the mass of the control system as well as provide an opportunity for failure of components.